1. Field of the Invention
This invention relates to the field of two-stroke internal combustion engines in which the oil is injected independently of the gasoline. These engines are also called engines with separate lubrication.
More specifically, the invention describes the monitoring of the flow rate, or metering, of the oil that is injected into this type of engine.
2. Description of the Prior Art
The known systems for oil metering generally comprise a mechanical metering pump that is controlled based on parameters such as the engine speed and/or the position of the gas throttle valve, representing the load of the engine.
These parameters, which are now used to control the metering of oil, have several drawbacks, particularly in the case of air-cooled engines. They do not make it possible, in particular, to ensure good metering regardless of the load and/or the speed of the engine. In particular, metering is unsuitable when the thermal level of the engine varies: when climbing a steep grade or in the event of a failure of the cooling system, for example.
Improvements have therefore already been proposed, such as, for example, in Patent Application EP-A1-0577081. According to this document, it is possible to readjust the amount of oil that is injected based on thresholds stored in a computer memory; it is also possible to vary the length of time between injections.
This technological solution is based primarily on the load and speed values of the engine.